Naked Capitalism has the article Goldman Makes It Official That the Stock Market is Manipulated, Buybacks Drive Valuations.
In fact, these companies are being gradually liquidated. Issuing debt, which public companies have done in copious volumes since the crash, and using it to buy shares is dissipating corporate assets. They are over time shrinking their businesses.
As an investor, this is something to keep in mind. I am not exactly sure what you do with this information, though.